1. Field of the Invention
The present invention relates to a device for accommodating voice terminals for voice communication in a switching unit.
2. Description of the Background Art
Today, studies and developments are under way for connecting, e.g., telephones dealing with voice communication and G3 facsimile apparatuses to a local area network (LAN) mainly dealing with data communication in order to implement integrated voice/data communication. For example, IP (Internet Protocol) telephones and personal computers or similar exclusive terminals may be connected, via network cables, to an integrated voice/data switching unit connected to a LAN. The IP telephone sets are capable of sending and receiving data in the form of IP packets. In such a configuration, the telephones and exclusive terminals are capable of holding voice communication with equipment also connected to the LAN.
An IP telephone, for example, includes a control circuit for assembling and disassembling voice packets and control packets, a multifunction CODEC, an input section including numeral keys, a display device including LEDs (Light Emitting Diodes) and an LCD (Liquid Crystal Display), a transmitter/receiver, and a LAN interface. This kind of telephone is capable of interchanging IP packets produced by packetizing a voice signal with an IP network and is a promising new voice communication apparatus.
On the other hand, a digital PBX (Private Branch Exchange) accommodates voice communication terminals including existing telephones belonging to a conventional telephone network. The digital PBX includes extension interfaces each designed for a particular terminal accommodated therein and provides various kinds of voice communication services. The terminals connected to the PBX may be key telephones by way of example. It follows that various kinds of services are expected even with IP telephones.
However, substituting the above integrated voice/data switching unit accommodating IP telephones and other terminals for all of an existing digital PBX system and analog telephone equipment is not desirable from the work and equipment cost standpoint although it will successfully integrate the entire voice communication base into a data communication network. Specifically, a conventional key telephone, for example, does not include a LAN interface and cannot be easily connected to an integrated voice/data switching unit. As a result, when an integrated voice/data switching unit is actually operated, all existing telephones lacking a LAN interface become useless.
To accommodate existing telephones in an integrated voice/data switching unit, it is necessary to newly develop and produce subscriber circuits, trunks or similar interface circuits in accordance with the telephones and switching unit by exclusive designing. This not only further increases the development cost, but also obstructs the effective use of existing equipment. Specifically, various line packages included in a digital PBX for accommodating the telephones cannot be used at all despite that analog telephones and interfaces including office lines and exclusive lines are unchanged.
As stated above, an efficient system implementing integrated voice/data communication with an integrated voice/data switching unit cannot be easily constructed with existing terminals and existing line packages.